Molluscicidal oxime carbamates

ABSTRACT

NOVEL USE OF OXIME CARBAMATES AS MOLLUSCICIDES.

United States Patent Ofirce ABSTRACT OF THE DISCLOSURE Novel use of oxime carbamates as molluscicides.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to the use of certain oxime carbamates as molluscicides.

Description of the prior art Certain alkylthiooxime carbamates are known to have slugicidal acti vity (Crowell; J. Econ. But. 60, 1048, 1967). The compounds of this invention, however, have significantly higher activity than the compounds disclosed in the above article.

SUMMARY OF THE INVENTION This invention relates to molluscicidal use of certain oxime carbamate compounds.

It has now been found that compounds of this invention exhibit outstanding molluscicidal activity particularly against gastropods of the group Stylommatophora.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention provides a method of combatting molluscs which comprises applying to a mollusc habitat a molluscicidally effective amount of a composition comprising, as active ingredient, an oxime carbamate of general formula:

wherein R is cyanoalkylthio of 1 to 6 carbon atoms, or alkynylthio of up to 6 carbon atoms; R is alkyl of 1 to 6 carbon atoms; R is alkyl of 1-2 carbon atoms.

Example's of these compounds include: 1-(5-cyano- :their high activity, are compounds of Formula I wherein R is propynylthio or butynylthio; R is alkyl of l to 3 carbon atoms. Examples of this class of compounds include: l-propargylthio acetaldoxime N-methylcarbamate,

l-propargylthio propionaldoxime N-methylcarbamate, l-

4 Claims 3,663,707, Patented May 16, 1972 propargylthio isobutyraldoxime N-methylcarbamate, 1-(1- rnethylprop-Z-ynylthio) acetaldoxime N-methylcarbamate, 1-(but-2-ynylthio) acetaldoxime N-methylcarbamate, and l-but-3-ynylthio)acetaldoxime N-methylcarbamate.

Another preferred subclass of these molluscicides, again because of their very high activity, are compounds of Formula I wherein R is cyanoalkyl of l to 4 carbon atoms; and R is alkyl of l to 3 carbon atoms. Examples of this class of compounds include:

1-( cyanomethylthio)acetaldoxime N-methylcarbamate,

1-(cyanomethylthio)propionaldoxime N-methy1- carbamate,

1-(2-cyanoethylthio)propionaldoxime N-methylcarbamate,

I-(Z-cyanoethylthio)isobutyraldoxime N-methylcarbamate,

I-(Z-cyanoethylthio) acetaldoxime N-ethylcarbamate,

l- (3-cyanopropy1thio acetaldoxime N -ethylcarbamate,

1-(3-cyanopropy1thio)acetaldoxime N-methylcarbamate,

1- (4-cyanoethylthio) acetaldoxime N-methylcarbamate,

1- (4-cyanobutylthio propionaldoxime N-methylcarbamate, and- 1- 4- cyanobutylthio isob utyraldoxime.

The compound most preferred for use in the method of the invention is 1-(2-cyanoethylthio) acetaldoxime N- methylcarbamate.

Oximes can exist in two stereoisomeric forms known as syn and anti, and this type of stereoisomerism exists also in the oxime carbamates of the present invention. Both stereoisomeric forms of the oxime carbamates, together with mixtures of the two forms, fall within the scope of the present invention.

It is Well known that many types of mollusc are agricultural and horticultural pests. The method of the invention is therefore particularly useful for the protection against attack by such molluscs of crops which are growing or are to be grown in a mollusc habitat.

Compositions suitable for use in the method of the invention comprise a compound of Formula I and a carrier or a surface-active agent or both a carrier and a surfaceactive agent, and also a food bait for the mollusc.

The term carrier as used herein means a material, which may be inorganic or organic and of synthetic or natural origin, with which the active compound is mixed or formulated to facilitate its application to the plant, seed, soil or other object to be treated, or its storage, transport or handling. The carrier may be a solid or a tfluid. Any of the material usually applied in formulating pesticides may be used as as carrier.

Examples of suitable solid carriers are silicates, clays, for example, kaolinite clay, synthetic hydrated silicon oxides, synthetic calcium silicates, elements such as for example, carbon and sulphur, natural and synthetic resins such as for example, coumarone resins, rosin, copal, shellac, dammar, polyvinyl chloride and styrene polymers and 'copolymers, solid polychlorophenols, bitumen, asphaltite, waxes, such as for example, beeswax, parafliu 'wax, montan wax and chlorinated mineral waxes, and

solid fertilizers, for example, superphosphates.

Examples of suitable fluid carriers are water, alcohols, such as for example, isopropanol, ketones, such as for ex 'ample, acetone, methyl ethyl ketone, methyl isobutyl The surface-active agent may be a wetting agent, an emulsifying agent or a dispersing agent; it may be nonionic or ionic. Any of the surface-active agents usually applied in formulating herbicides or insecticides may be used. Examples of suitable surface-active agents are the sodium or calcium salts of polyacrylic acids, the condensation products of fatty acids or aliphatic amines or amides containing at least 12 carbon atoms in the molecule with ethylene oxide and/or propylene oxide; partial esters of the above fatty acids with glycerol, sorbitan, sucrose or pentaerythritol; condensation products of alkyl phenols, for example, p-octylphenol or p-octylcresol, with ethylene oxide and/or propylene oxide; sulphates or'sulphonates of these condensation products; and alkali metal salts, preferably sodium salts of sulphuric or sulphonic acid esters containing at least 10 carbon atoms in the molecule, for example, sodium lauryl sulphate, sodium secondary alkyl sulphates, sodium salts of sulphonated castor oil, and sodium alkylaryl sulphonates such as sodium dodecylbenzene sulphonate.

The compositions of the method of the invention include a food bait for the mollusc, which may also act as carrier for the toxicant. The mollusc food bait may be wheat, corn, barley, maize, rice, bran, groundnut, or any other vegetable product used for animal feeding. One or more of the following substances may be used as a supplement to the mollusc food bait, making the food bait more palatable to the mollusc:

(a) a B vitamin, particularly, B1, B2, B6, nicotinic acid or nicotinamide.

(b) vitamin E.

(c) an animal or vegetable proteinaceous material, for example, albuminoids and their hydrolytic degradative products, particularly those obtained by enzymic hydrolysis, for example, with pepsin, such as a metaproteins, proteoses, peptones, polypeptides, peptides, diketopiperazines and amino carboxylic acids.

(d) one or more amino carboxylic acids or their salts or amides which may be synthetic products.

(e) a nucleic acid or a hydrolytic degradation product thereof such as a nucleotide, a nucleoside, adenine, guanine, cytosine, uracil or thymine.

(f) urea, carbamic acid.

(g) an ammonium salt, for example, ammonium acetate.

(h) an amino sugar, for example, glucosamine or galactosamine.

(i) sodium, potassium, calcium or magnesium compounds or trace amounts of manganese, copper, iron, cobalt, zinc, aluminum, boron or molybdenum compounds, particularly chelates thereof such as versenes.

(j) phosphoric acid or glyceryl or sugar phosphates.

The compositions may be formulated in any of the ways used for formulating pesticides. Particularly suitable formulations are granules or pellets comprising 0.5- 25, preferably 2-10% w. toxic and up to about 50% W. bait attractant. The granules or pellets may be manufac tured by any of the known techniques, for example, by agglomeration, extrusion, compaction or stick-on techniques. Granules are usually prepared to have a size between 10 and 100 BS mesh. The formulations preferably also include 0.l-5% w. preservative, 05-20% W. binding agent and -70% w. slow release modifiers.

The incorporation of a preservative into the compositions inhibits the occurrence of fungal and/or bacterial growth on or in the compositions, and thus largely overcomes any problems of deterioration in use or from storage for long periods. Any food preservative known to the art as haivng fungistatic or fungicidal and/or bacterial or bacteriostatic action may be used, for example, sodium benzoate, methyl p-hydroxybenzoate, cetyl trimethyl ammonium bromide, citric acid, tartaric acid, sorbic acid, a phenol, an alkyl phenol or a chlorinated phenol.

'In order to facilitate the formulation of the composition, it may be desirable to. incorporate into it one or more suitable binding agents such as alginic acid, alginates, alginate esters, starches, dextrins, cellulose derivatives and glues.

In view of the relatively high water solubility of the compounds of the invention, it is preferable to include in the composition one or more slow release modifiers in order to obtain a controlled release of the toxicant. Suitable release modifiers include clays, such as bentonite or kaolinite, silicon oxides, polymeric materials such as cellulose, cellulose ethers, particularly cellulose acetate, and resins, for example, urea formaldehyde resins, soya flour, waxes stearates and oils, for example, castor oil.

A suitable dye, for example, a blue dye, may be also incorporated into the bait granules or pellets to render them unattractive to other forms of wild life, such as birds, and domestic animals.

The majority of the oxime carbamates used in the method of this invention are described and claimed as novel compounds in one or more of British Pat. Nos. 1,090,986, 1,101,785, 1,138,057, 1,166,144, and 1,198,023, wherein details of the synthetic and physical properties of the compounds are disclosed. Accordingly, this specification will provide these data only in respect of those compounds which are not specifically mentioned in the earlier cases just named. As disclosed in these earlier cases, the compounds may be prepared by reacting an oxime of formula:

with a carbamoyl halide of formula:

or alternatively with an isocyanate of the formula RgNOO, or with phosgene and the appropriate substituted amine of formula R NHR in the presence of a base, preferably an organic base such as a trialkylamine. In these formulae, Hal represents a halogen, preferably chlorine, atom and R R R and R have the meanings defined in respect of Formula I.

The compounds of the invention, their method of preparation and their molluscidal activity, together with bait formulations containing them, are illustrated in the following examples, in which parts by weight (w.) and parts by volume (v.) bear the same relation as the kilogram to the liter.

EXAMPLE l.tPROPARGYLTHIO-ACETAL- DOXIME N-METHYLCARBAMATE l-propargylthio-acetaldoxime (7.2 w.) in dichloromethane v.) was treated with triethylamine (1 drop) and methyl isocyanate (50 v.) and the mixture was heated under reflux for 1 hour. The solution was then evaporated to small volume and the residual oil chromatographed on silica gel. On elution with dichloromethane, a yellow oil was obtained, which soon solidified. This Following a method similar. to. thatdescribed in Example I further compounds wer'e'prepared, whose physical characteristics and analysis figuresj'are summarized in Table 1.

TABLE 1 Melting I Analysis, percent point,

Compound C- C H j S l-propargylthio-pro- 52-53 CaHnNzSOr:

pionaldoxime N- Galculated .--48.0 6.0 --16.0

methylearbamate. Found 47.8 6.0 15. 9

1-(1-Inethylprop-2 70-71 C3H1LYN2SO22 ynylthio)-acetal- Caleulated.. 48. 6. 1 14.0

doxime N'Inethyl- Found 48.7 6. 5 l4. 5

earbamate.

l-propargylthio- 83. 5-84. 5 CDHHNQSOQ:

isobutyraldoxime N- Calculated. 50. 6 6. 6 l4. 9

methylcarbamate. Found 50. 5 6.5 14. 6

1-(2-cyanoethylthio) CnHrsNaSOzi isobutyraldoxime N- Calculated-. 47. 1 6. 6 18. 3

methylcarbamate. Found 46.8 6.7 17.8

l-(but-Z-ynylthio) 6l-62 C8Hl2N2sO2Z acetaldoxime N- Calculated 48.0 6.0 14

methylcarbamate. Found 47.8 6.1 .3

1-(but-3-ynylthio) 55-57 CaHizNzs er aeetaldoxime N Calculated. 48.0 6.0 14. 0

mothylcarbamate. Found 48.4 6. 2 13.8

EXAMPLE I-II.-BAIT FORMULATIONS Bait granules having the composition given in Table 2 were prepared by the following method. The ingredients were blended together by hammer-milling and water was added to the mixture to form a still dough. The dough was then extruded and cut into granules which were then dried at 70 C. and screened to British Standard sieve 10-60 mesh size.

TABLE 2 Composition of granules, percent w.

Ingredient 1 2 3 4 5 6 7 8 9 l-cyanomethylthio acetaldoxime N- methylcarbamate 5.0 5.0 5.0 l-(2-eyanoethylthlo) acetaldoxime N- methylcarbarnate 5.0 5.0 5.0 1-(3-eyanopropylthio acetaldoxime N- methylcarbamate 5.0 5.0 5.0 Sodium benzoate. 1.0 1.0 1.0 1.0 1.0 1.0 1.0 11.0 1.0 Alginic acid binder" 9.0 9.0 9.0 9.0 9.0 9.0 9.0 9.0 9.0 Cellulose acetate 40.0 40.0 40.0 Silicondioxide K320 40.0 40.0 40.0 Wheat bran To 100% w.

EXAMPLE IV.MOLLUSCICIDAL ACTIVITY The molluscicidal activity of the compounds used in the method of the invention was tested by one or more of the following methods, using as test molluscs, fieldcollccted specimens of the grey field slug Agriolimax reticulams.

6 (1) Oral tests (a) A 2 /2 bait was prepared by dissolving a fixed weight of the test compound in acetone, mixing this solution with the appropriate amount of milled bran and allowing the acetone to evaporate. 0.5 g. of this bran bait was sprinkled over the surface of a moist filter paper in a Petri-dish and 4. specimens of A. reticulatus wereintroduced and left exposed to the bait for 24 hours. The slugs were then transferred to a clean Petri-dish containing moist filter paper and fresh lettuce and after 48 hours the mortalities were recorded.

(b) 0.05 g. of a 2.5% bran bait prepared as in (a) was placed on a small cavity slide on damp filter in a Petridish. 5 adult specimensof A. reticulatus were introduced into the Petri-dish and left exposed to the bait for 24 hours at 10 C, A duplicate test was carried out for each of the test compounds. After the exposure period the slugs'lwere transferred to clean dishes each containing a 1" diameter cabbage leaf disc as food. Mortalities were assessed every 24 hours for 6 days.

(2) Contact tests (c) The contact activity of certain of the test compounds was assessed by spraying a solution of the toxicant onto a moist mud surface to give a concentration of 2 kg. toxicant/ha. Specimens of A. reticulatus were introduced and exposed to the surface for 24 hours. Recovery was on fresh lettuce as in test (a) above.

(d) 2 ,ul. of a2% solution of the test compound in acetone (or dimethylformamide if insoluble in acetone) was applied to the foot of each test slug with a micro topical applicator. 10 specimens of A. reticulatus were used for each of the test compounds. The slugs were placed on damp filter paper in Petri-dishes at 10 C. with cabbage leaf discs as food supply. Mortalities were assessed every 24 hours for 6 days.

The results of the tests (a)-(d) are set out in Table 3.

TABLE 3 Percent mortality A.

reticulatue Oral tests Contact tests Compound (2.) (b) (c) (d) l-(eyanomethylthio) acetaldoxime N methyl carbamate 0 100 100 l-(cyanomethylthio) propionaldoxime N- methylcarbamate 100 60 100 1-(cyanoethylthio) acetald methylearbamate 100 100 1-(cyanoethylthio) pr methylcarbamate. 20 100 100 1-(2-eyanoethylthib) methylcarbamate 40 100 1-(2-eyanoethylthio) acetaldoxlme N- ethylearbamate 0 100 1-(3-cyanopropylthio) acetaldoxime N- methylcarbamate 100 10 1-(3-eyanopropylthio) propionaldoxime N- methylcarbamate 100 1-(4-cyanobutylthio) aeetaldoximo N- methylcarbamate 100 0 20 1-(4-cyanobutylthlo) propionaldoxime N- mothylcarbamate 100 80 1-(4-cyanlbutylthio) isobutyraldoxime N- methylearbamate 100 l00 l-(5-cyanopentylthio) acetaldoxime N- methylearbamate 100 80 l-(o-cyanohexylthio) acetaldoxime N- methylcarbamate 100 l-propargylthio aeetaldoxime N methylearnamate 100 40 100 l-propargylthio propionaldoxime N- methylcarbamate 100 100 l-propargylthio isobutyraldoxime N- methylcarbamate 100 50 100 100 1-(l-methylpropr2-ynylthio) acetaldoxime N-methylearbamate 100 50 100 0 1-(but-2-ynylthio) acetaldoxime N- methylearbamate 0 2 1-(but-3ynylthio) aeetaldoxime N- methylcarbamate 40 40 M 3,663,707 7 h a We claim as our invention: 3. A 'methodaccording to claim 1 wherein R is 1. A method of combatting molluscs which comprises cyanoalkyl of 1 to 4 carbon atoms; and R is alkyl of 1 to applying to said molluscs a molluscicidally effective amount 3 carbon atoms. of an oxime carbamate of the following formulap 4. A method according to claim 3 wherein R is 2- 5 cyanoethylthio; R is methyl; and R is methyl.

References Cited m c R1 1 1 FOREIGN PATENTS N=NoN 10 1,090,986 11/1962 Great Britain. H 7 1,101,785 1/1968 GreatBritain.

1,138,057 12/1968 Great Britain.

v OTHER REFERENCES wherein R is cyanoalkylthio of 1 to 6 carbon atoms or 5 Crown, H Econ Em vol. 60, No. 4 (1967), pp. alkynylthio of up to 6 carbon atoms; R is alkyl of 1 to 1048, 1049 p U V V V 6 carbon atoms; and R is alkyl of 1 to 2 carbonatoms. V 1 Y 2. A method according to claim 1 wherein R is ALBERTT MEY propynylthio, l-methylpropynyl or butynylthio; and R 7 3 i Examiner is alkyl of 1 to 3 carbon atoms. 20 V. D. TURNER, Assistant Examiner 

